As for a PDF version, I couldn't confirm whether an official or unofficial PDF of "Elden Ring Los Libros Del Saber Volumen I" exists. Be cautious when searching for PDFs, as they might be unofficial leaks or scans, which could be subject to copyright issues.

"Los Libros Del Saber" (The Books of Knowledge) seems to be a series of books related to Elden Ring, possibly a companion to the game or a source of lore and background information.

The "Volumen I" you're referring to likely indicates that this is the first book in the series. Unfortunately, I couldn't find much information on the specific contents of this book.